From be1c63411addba3ad750eb4fdfc50b97bc82825e Mon Sep 17 00:00:00 2001 From: Olaf Kirch Date: Fri, 1 Dec 2006 10:39:12 +0100 Subject: [PATCH] blktrace: add timestamp message This adds a new timestamp message to blktrace, giving the timeofday when we starting tracing. This helps user space correlate block trace events with eg an application strace. This requires a (compatible) update to blkparse. The changed blkparse is still able to process traces generated by older kernels, and older versions of blkparse should silently ignore the new records (because they have a pid of 0). Signed-off-by: Olaf Kirch Signed-off-by: Jens Axboe --- block/blktrace.c | 57 ++++++++++++++++++++++++++++++++++++++++++++------------ 1 file changed, 45 insertions(+), 12 deletions(-) (limited to 'block') diff --git a/block/blktrace.c b/block/blktrace.c index 135593c8e45..562ca7cbf85 100644 --- a/block/blktrace.c +++ b/block/blktrace.c @@ -22,30 +22,61 @@ #include #include #include +#include #include static DEFINE_PER_CPU(unsigned long long, blk_trace_cpu_offset) = { 0, }; static unsigned int blktrace_seq __read_mostly = 1; +/* + * Send out a notify message. + */ +static inline unsigned int trace_note(struct blk_trace *bt, + pid_t pid, int action, + const void *data, size_t len) +{ + struct blk_io_trace *t; + int cpu = smp_processor_id(); + + t = relay_reserve(bt->rchan, sizeof(*t) + len); + if (t == NULL) + return 0; + + t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; + t->time = sched_clock() - per_cpu(blk_trace_cpu_offset, cpu); + t->device = bt->dev; + t->action = action; + t->pid = pid; + t->cpu = cpu; + t->pdu_len = len; + memcpy((void *) t + sizeof(*t), data, len); + return blktrace_seq; +} + /* * Send out a notify for this process, if we haven't done so since a trace * started */ static void trace_note_tsk(struct blk_trace *bt, struct task_struct *tsk) { - struct blk_io_trace *t; + tsk->btrace_seq = trace_note(bt, tsk->pid, + BLK_TN_PROCESS, + tsk->comm, sizeof(tsk->comm)); +} - t = relay_reserve(bt->rchan, sizeof(*t) + sizeof(tsk->comm)); - if (t) { - t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; - t->device = bt->dev; - t->action = BLK_TC_ACT(BLK_TC_NOTIFY); - t->pid = tsk->pid; - t->cpu = smp_processor_id(); - t->pdu_len = sizeof(tsk->comm); - memcpy((void *) t + sizeof(*t), tsk->comm, t->pdu_len); - tsk->btrace_seq = blktrace_seq; - } +static void trace_note_time(struct blk_trace *bt) +{ + struct timespec now; + unsigned long flags; + u32 words[2]; + + getnstimeofday(&now); + words[0] = now.tv_sec; + words[1] = now.tv_nsec; + + local_irq_save(flags); + trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words)); + local_irq_restore(flags); } static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector, @@ -394,6 +425,8 @@ static int blk_trace_startstop(request_queue_t *q, int start) blktrace_seq++; smp_mb(); bt->trace_state = Blktrace_running; + + trace_note_time(bt); ret = 0; } } else { -- cgit v1.2.3